Heartworm

There are two broad categories of worms that may affect our pet dogs and cats, heartworm and intestinal worms.  Please see our intestinal worm page for more information.

Heartworm
Heartworm, or Dirofilaria immitis, is a parasite that is spread by mosquitoes. This means your pet does not even need to be in contact with other pets to become infected! The disease can be found all over Australia (except Tasmania and arid areas) and protection against this disease is vital not only to minimise the spread of heartworm but as infected pets can only be managed, not cured.

Heartworm has a complicated life cycle. Infected pets have microfilaria - which are minute young heart worms - circulating in their bloodstream. Microfilariae are sucked up by mosquitoes when feeding on the blood of an infected animal. The immature parasite develops into a heartworm larva inside the mosquito, then a single bite from a carrier mosquito can infect your pet (dog or cat). As the worms mature in the heart they can cause a physical blockage as well as thickening of the heart and associated blood vessels. The worms also produce offspring (microfilaria) which are then sucked up by a mosquito when it bites the infected animal. And so the cycle starts again.

In the early stages of infection there may be no visible signs, however, infection may eventually lead to signs of heart failure (coughing, reluctance to exercise, lethargy). In advanced cases, fluid leaks from the blood vessels and accumulates in the lungs and lower part of the abdomen. Sometimes the animal suddenly collapses without warning with deep, laboured breathing, extreme weakness and a blue appearance to the tongue, with very pale gums. If left to progress untreated Heartworm can result in death. In cats, heartworm disease is uncommon. The worms don’t survive well in a cat’s body and are usually unable to breed. However, occasionally disease can be caused with just one worm (dogs can generally tolerate two). Tragically, the most common sign of the disease in cats is sudden death, but breathlessness and a cough should also have you concerned.

Treatment of this disease is expansive and requires long term after care so prevention is definitely the best choice and thankfully is very easy and effective with many options. These options include tablets, chews, spot-on's and even an annual injection for dogs administered by one of our vets. If you have an adult pet that has not been on heartworm prevention we recommend a heartworm test prior to starting a prevention program, followed by a repeat test 6 months after commencing.


Please call us to discuss the best heartworm prevention for your pet.